When two mobile users make a call through mobile terminals such as mobile phones or smart phones, important call information is often generated and needs to be recorded. The information may include, for example, a phone number or a contact address from the other party. Since the two mobile users are usually at uncertain locations during the call and may not be able to write down the information on a paper note, the information may be obtained by recording a voice call associated with the call after the call ends, from which the information may be extracted.